Method and apparatus for drawing sheet glass



Patented Nov. 21, 1922.

3 SHEETS'SHEET X- J. P. CROWLEY. METHOD AND APPARATUS FOR :JRAwme SHEET GLASS. APPLICATION FILED AUG. r. 1920. 1,435,956

INVENTOR M0552 P C/Pon/L E Y BY f /7'/$ .4 7'7'0Q\/EY J. P. CROWLEY.

METHOD AND APPARATUS FOR DRAWiNG SHEET GLASS! APFLECAHON HLED AUGJ, 192m,

1,435,956. Patented Nov. 21, 1922.

3 SHEETS-SHEET 2.

tfosfph' H CH0 WLEY 5 MMQ J. P. CROWLEY.

METHOD AND APPARATUS FOR DRAWING SHEET GLASS. APPLICATION m5!) AUG. 7} 1020.

1 ,435,956, Patented Nov. 21, 1922.

3 SHEETS-SHEET 3.

4/ INVENTOR r/OSEPHP Oman/LE Patented Nov. 21, 1922.

UNITED STATES rATENT OFFICE.

JOSEPH P. CROWLEY, OF TOLEDO, OHIO, ASSIGNOR TO THE LIIBBEY-OWE-NS SHEET GLASS COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO.

METHOD AND APPARATUS FOR DRAWING SH EE'I GLASS.

Application filed August '7 1920. Serial No. 01,839.

To all whom it may concern: i

Be it known that I, Josnrn P. CRowLnY,

- a citizen of the United States, residing at from a pot or receptacle. containing molten glass, the glass at the sides,fr0m which the edges of the sheet are formed. is cooler and less plastic than. the glass at the center from which the main body of the sheet is formed. This is due primarily to the proximity of this glass to the sides of the receptacle, and is also often accentuated by artificial cooling means, it being desirable to have the edge portions of the sheet cooler and stiffer to maintain the width of the sheet. This cooler and less plastic glass will, of course, flow less readily into the sheet and it is customary to employ some auxiliar drawin means to assist in pulling up this sti er glass. as for example the edge rollersshown in the patent to Colburn, Reissue 14.794, Jan. 27, 1920.

It is an object of this invention to force this cooler glass at the sides to flow toward and into the forming sheet, so as to provide a constant supply of cool glass at the sheet edge sources, and in practicing the invention a plurality of teeth or pickers, moving in closed paths or orbits above the surface of the molten mass, dig into the cooled surface of the glass mass and tend to carry it toward, and upwardly into the sheet. These teeth or pickers are tools to prevent the hot glass from adhering thereto, and the'contact with, and proximity of, these cooled members to the molten glass the sides of the receptacle tends to further cool and stiffen the glass thus forming the desired stifl edge portions on the drawn sheet.

Molten glass, if allowed to cool slowly,

without "being kep: in. motion, tends to devitrify .or form so-called dog metal, and this trouble has often been experienced at the sides of the receptacle from which the edge portions of the sheet are drawn. A further object of this invention is to prevent this devitrification, by keeping the glass in motion at the sides of the receptacle.

y stirring up and preventing the premature setting of the surface portion of the molten glass, this invention also tends to eliminatethe formation of waves or undulations which often injure the quality of drawn sheet glass.

Further objects and advantages of this invention will, appear as,the description proceeds.

In the accompanying drawingsilshpwingi e inventhree practical embodiments oft tion: i

Fig. 1 is a central vertical section through the sheet and that end of the apparatus from which the sheet is drawn;

Fig. 2 is a partial plan view of one pair of the molten glass manipulating devices for carrying out this invention, the sheet being shown in transverse section.

Fig. 3 is a view similar to Fig. 2 with the teeth or pickers arranged at a different.

an le to the plane of the sheet.

. ig. 4 is a side elevation of a modified form 0? the invention, one edge only of the sheet being shown in side elevation, and the drawing receptacle shown in vertical section. v

Fig. 5 is a partial inner end elevation of the glass pickers, and

Fig. 6 is a similar view showing the pickers in a different working position.

Fig. 7 is an outer end elevation of the supporting and adjusting frame for the pickers, and i i Fig. 8 is a cross-section on the line 8-8 of Fig. 7.

Fig. 9 is a cross-section of one of the pickers showin the water-cooling system.

Fig. 10 is a side elevation, similar to Fig. 4, showing a third modificationot the invention.

Fig. 11 is a plan view of air of the pickers, and their operating; mechanism according to this form of the invention.

in section on the line 12 512of 1 .10 of the cam mechanismfor operating to" 'ickers'.

Fig. 13 is a transverse section oi t e sup porting bracket and slide plate on the line 13-13 of Fig. 10.

Fig. lat is a partial elevation of the upper end of the supporting slide-plate.

Referring first to Figs. 1, 2 avid 3 of the drawin s, which illustrate the preferred form of apparatus for carrying out my invention, 1 is the end of the cooling tank from which the refined molten glass 2 flows into the drawing receptacle 3. The apparatus so far described, as well as all of the system for melting, refining and preparing the glass for the drawing operation, may be of any well-known form such for example as that shown in the patent to Colburn, 1,248,509, granted Dec. 4, 1917. The molten glass in the drawing receptacle is retained at the proper temperature by the burners fl, under the shielding lip-tiles 5, and the glass at the drawing point, which is exposed in the atmosphere, is tempered by the water-.

coolers 6. The glass sheet T is drawn up from this cooled surface, passed over the cooled bending-roll ti, and intermediate sup porting roll 9, and drawn off in a. hori zontal direction by suitable drawing and flattening devices into the annealing leer.

.All of this is common practice in this art, as

shown for example in the (olburn patent above referred to. It. is understood that other sheet enclosing, heating and cooling devices than those shown, are employed at different stages of the sheet forming process. but as these features may be of old and well-known form they will not he further described.

The glass at the sides of the receptacle, from which the edge portions ill of the sheet are drawn, is cooler and less plastic than the glass at the central portions of the receptacle. This is due in part to therelative proximity of this glass to the cool sides of the pot or receptacle, and in part to the presence of the watcnmoled glassl'eediug devices now about to he described. Mounted above, and substantially parallel to the sur face of the molten mass, at each side of each edge of the sheet 7, is a hollow rotary shaft ll, each being rotated in the direction of the arrows shown on the drawings, by any suitable driving means. At the inner end of each shaft is mounted a circular series of teeth or pickers 12, somewhat resembling a sprocket-wheel in appearance. The shafts and pickers are internally cooled by a corn stant flow of water, which passes in through an inner pipe 13, and out around this pipe through the hollow shaft 11. While in the lower portion of their orbit, the teeth 12, dig into the surface portion of the glass mass, cooling the same and tending to set up a flow of the glass inward toward thc sheet. As the teeth rise on the inner portion of their orbit they tend to carry the glass upward into the sheet, and the combined action of the two sets of teeth or pickers is to keep up a constant flow of cooled, stiff, glass, into the edges of the sheet, and to build up a reserve mass of glass at 14 for readily feeding into the sheet. edges. An ample supply of cool glass is thus maintained at the sources of the sheet edges,.and this lass is much cooler and stiffer than the Sass at the central portion of the receptacle. A much greater tension or pulling strain is necessary to pull the sheet edge portions from this less plastic glass, and this added tension at the edges tends to maintain the width of the sheet. and overcome the tendency to narrow that is present in all sheet drawing operations.

By keeping the glass in motion along the sides of the receptacle the cooling glass is prevented from devitrifying and forming dog metal.

The shafts may be arranged parallel to the sheet faces, so that the paths or orbits of the. teeth are at right angles to the sheet, and the flow of glass will he at right angles to the sheet, as shown in Fig. 2; or the shafts may be arranged at any desired angle to the sheet faces, as shown for example in Fig/ll, so that the flow of glass will. be outward, toward the receptacle walls, thus adding a certain lateral stretch to the sheet. Any desired number of teeth 12 may be used on each shaft, and the speed of rotation of the shafts is capable of adjustment so as to maintain the proper {low of glass to the sheet edge sources.

It will be noted that in this. and both succeeding forms of the apparatus used, there is no contact at any point between the teeth or pickers and the formed sheet so that the edge will draw smooth and unmarred.

ln the modification shown in l 'h r to J inclusive, :1 pair of teeth or pickers 15. at the lower ends of vertically extending levers lt'. are positioned, one at cach side of each edge of the sheet T, as shown in Figs. 4 and These levers it) are in the form of hollow tubes or pipes and are internally watercooled, as in the form of the invention first described. The water flows in through pipe .17, aml inner pipe 18 to and through the picker 15, then out through the hollow lever lti-and )ipe connection 1!), as all shown more particularly in Figs. 4 and 5).

The members it) are vertically slidahle through tubular guides 20 at the ends of roclcshafts .21, pivoted at 22 in the slidable frame 23. Near their lower ends, the members ll; are secured, by means of adjusting screws .24, in sleeve members 25, eccentrically pivoted at 20, in the ends of rotatable shafts 27. "lhese shafts 27 are rotatably mounted in slidable frame 28, and are geared together by gears 29], to rotate simultaneously in opposite directions. 'lhese shafts re driven by any suitable means such 1 ,asspuc that their speed can be varied as found de sirable. The frame 23 is slidably mounted in upright extensions on frame 28, which in turn are-slidably mounted in a fixed frame member 30, all as clearly shown in Figs. 7 and 8..- The 'frames 23 and 28 are adjustable vertically, relative to frame 30 and to each other by means of the. adjusting screws 31 and 32 respectively. By proper manipulation of these adjusting devices the position of the pickers 15 relative to the surface of the molten glass and the size of the orbits described by these pickers can be adjusted as desired. The paths followed by these pickers 15" when in operation are shown in dotted lines all! Hi 6.

In the modification shown in Figs. 10 to 14 inclusive the pickers 33 are formed as vertical downward extensions of horizontal 46 and 47 have ri ht slide late 41. This plate 41 i ,5 42 in the su shafts'34, adjustably secured in sleeve mem here 35 by screws 36. The pickers 33 and shafts 34 are internally water-cooled in the same mannen'as already described in connection with Figs. 4 to 9. The two sleeve members35 are pivoted on vertical axes 37 and 38, respectively, on a bell-crank lever 39, horizontally pivoted at 40, on an upis adjuste vertic 1y, by means of adjusting screw portingbracket 43, which has vertical gui e slots in which the plate is mounted. By proper manipulation of the adjusting screws 36 and 42, the positions of the pickers with relationto the surface of the'molten massand the edge of the sheet can be varied as found to be desirable. At the lower outer ends of sleeves 25 are vertically pivoted rollers 44 and 45 which operate in cam slots 46 and 47 respectively, in cam members 48 and 49 secured to the constantly rotating horizontal shaft 50. The cam slots their corresponding portions oppositely inclined, as shown in Figs. 11 and 12, so, that rotation of the cams 48 and 49 will cause the sleeves 35 and hence the shafts 34 and pickers 33 to oscillate to and from each other, and the sheet 7. Theperipheries termediate connecting of the cams 48 and 49 are eccentric to the shaft 50, each havinghigh concentric ortions 51, low concentric portions 52, and ininclined portions 53,

aszshown in Fig. 11. On the inner adjacent ends of the cam members are cam slots 54,

. each following the contour of the periphcries of the cam members. Guided in these cam slots 54 are rollers 55 pivoted at the outer end of bell-crank 39. The effect of these slots .54 is to oscillate the bell-crank,

and hence the pickers 33 inc. vertical plane. The elevated osition .of one of the pickers is shown in dbtted lines in Fig. 11'. The combined effect of the two sets of cam slots 46 and 47 and-54m to causeeach of the ickers to follow an elliptical path dipping lnto the glass bath in the lower portions of with the flow enforcin their orbits and carrying the cooled glass inwardly toward the sheet.

In each form of the invention shown, the effect of the moving teeth or pickers is to dip into and cool the glass and simultaneousl set up a circulation of the cooled glass at t e sides of the receptacle inwardly toward the forming edges of the sheet, thus overcoming the tendency of the glass at the sides to devitrify, and also maintaining a constantly replenished supply of cool stii'l' glass at the sources from which the sheet ed es are drawn.

bviously many other forms of the operating mechanism for carrying out this inventioncould be devised without departing from the scope of the invention as outlined these edge sources and the intermediate molten glass.

'2. The method of continuously drawing sheetf glass, which consists in preparing a mass of molten glass, chilling those portions of the surface of the molten mass from which the edge portions of the sheet are drawn, and simultaneously mechanically propelling these chilled portions upwardly into the sheet, and drawing a sheet of 'glass upwardly. from these edge sources and the intermediate molten glass.

3. The method of drawing sheet glass, which consists in preparing a mass of molten glass wherein the portions from which the edges of the sheet are formed are cooler than the intermediate portion, drawing u wardly a sheet of glass, and mechanical y assisting the cooler and less plastic surface portions at the edges to flow into the edges of the sheet, the entire width of the drawn sheet being out of contact with any forming means. 1 a

4. The method of drawing sheet glass, which consists in preparing a mass of molten glass wherein the portions from which the edges of the sheet are formed are cooler than the intermediate portion, drawin a sheet of glass from the molten mass, an positively enforcinga flow of the cooler and less plastic glass at the sheet edge sources into the edges of the sheet to supplement and assist the drawing action, and maintaining the entire width of the drawn sheet free from contact means.

rawing apparatus, a

mass of molten lass,

sheet of glass t em- 5. In a sheet glass receptacle containing a means for drawing a from, and with maintaining means for cooling and positively moving those portions of the molten mass lrom which the edges of the sheet are drawn outwardly and upwardly into the forming sheet, without contacting with or niarring the sheet.

0. In a sheet glass drawing apparatus, a receptacle containing molten glass, means for drawing a sheet of glass upwardly therefrom, and a plurality of teeth or pickers for causing those portions of the molten mass from which the edges of the sheet are drawn to flow into the edges of the sheet, the teeth not contacting with the drawn sheet.

7. In a sheet glass drawing mechanism, a receptacle containing molten glass. means for drawing a sheet of glass upwardly therefrom, and a plurality of water-cooled moving teeth or pickers for continuously chilling the surface portions of the molten mass from which the edges of the sheet are drawn, and forcing these chilled portions to more upwardly and outwardly into the edges of the sheet, the teeth remaining out of contact with the drawn sheet.

8. In a sheet lass drawing mechanism. a receptacle containing molten glass, means for drawing a sheet of glass upwardly therefrom, and water-cooled moving teeth or pickers for chilling the surface portions of the molten mass from which the edges of the sheet are drawn, and forcing these chilled portions to move upwardly into the edges of the sheet, the teeth remaining out of contact with the drawn sheet.

9. In a sheet glass drawing a )paratns, a receptacle containing molten g ass, means for drawing a sheet of glass upwardly therefrom, and internally-cooled moving teeth or pickersfor chilling the surface portions of the molten I'IHISS from which the edge portions of the sheet are drawn, and forcing these chilled portions to more into the edges of the sheet, the teeth remaining out of contact with the drawn sheet.

10. In a sheet glass drawing apparatus, a receptacle coi'itaining molten glass, means for drawing a sheetol glass upwardly therefrom, pairs o'l coi'itinuously rotating shafts located above the surface of the molten mass at each edge of the sheet, the sheet passing between the ends of each pair of shal'ts, and a circular series of teeth or pickcrs carried by each shaft, and moving into and with the surface portion of the glass toward the forming sheet, and means for internally cooling the pickers, whcrehy the surface of the molten mass at the edges of the sheet is chilled and carried into the shcet,'the pickers remaining out of contact with the drawn sheet.

ll. In a sheet glass drawing apparatus, a receptacle containing molten glass. means for drawing a sheet of glass upwardly therefrom, pairs of continuously rotating shafts located above the surface of the molten mass at the edges of the sheet. the sheet passin hetwecn the ends of each pair of shafts, and a circular series of teeth or pickers carried h each shaft. and moving into and with the surface portion of the glass toward the forming sheet for assisting the edge portions of the molten mass to flow into the sheet, the pickers remaining out of contact with the drawn sheet.

Signed at Toledo, in the county of Lucas and State of Ohio, this 5th day of August. 1920.

JOSEPH I. CROWLEY.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,435,956, granted November 21, 1922, upon the op lication of Joseph P. Crowley, of Toleoo, Ohio, for on improvement in Me ods and Apparatus for Drawing Sheet Gl'ass, on error appears in the printer] spccific'ntmn 'requirin correctlo'n ls follows: Page line 1, claim 5, for the word with" read widti; and that the said Letters Potent should be read with this correction therein that the same may conform to the record of the ease in the Patent Oflice.

Signed and sealed this 6th day of February. A. 1).. 1923.: 

